<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>数组合并</title>
</head>
<body>
  <script>
    // 合并数组 arr1 和数组 arr2。不要直接修改数组 arr，结果返回新的数组
    function concat(arr1, arr2) {
   return (arr1+","+arr2).split(",")
}
  </script>
</body>
</html>